Materials of the RMnO$_3$ (R is a rare-earth) multiferroic perovskite family show an extraordinary number of applications in technology, e.g., spintronic devices, data storage equipment, and sensors, thanks to properties like magnetically induced ferroelectricity. According to the literature, the Perturbed $\gamma-\gamma$ Angular Correlation (PAC) method is an available technique to study...
For nuclei with N around 50, several pieces of evidence supporting shape coexistence close to $^{78}$Ni have been found. In particular, the $\sim$940-keV 1/2$^+$ isomeric state in $^{79}$Zn has been interpreted as an intruder state, related to neutron excitations across N=50. Laser-spectroscopy measurements found a large isomeric shift for this state with respect to the $^{79}$Zn 9/2$^+$...
To efficiently laser-ionize many different elements, the spectral range of the Ti:Sa lasers at ISOLDE RILIS is extended with nonlinear processes of second-, third- and fourth harmonic generation (SHG, THG and FHG).
We present a technique to intracavity generate ns pulses in the tripled Ti:Sa range (~ 230nm – 310nm) with a Gaussian beam shape and a size comparable to that of the fundamental...
The Raman nonlinear process consists in a scattering interaction between light and a crystal. Through the process, light losses energy to a phonon of the crystal, leading to an up-shift in the laser wavelength. This wavelength shift can be used extend the laser frequency covered by the RILIS system, and hence improve its versatility.
During the past years, different laser designs have been...
Abstract for MULTIPAC draft for Users Meeting
MULTIPAC is a spectrometer that can perform γ-γ time-differential perturbed angular correlation (γ-γ TDPAC) experiments under controlled conditions such as an applied external magnetic field up to 8.5 T and temperatures ranging between 3 to 375 K. MULTIPAC differs from conventional γ-γ TDPAC spectrometers in the use of modern multi-pixel photon...
The electric dipole (E1) polarizability has recently been used to explain the universality of elemental abundances [1]. Here, we present shell-model (SM) calculations of the E1 polarizability for the ground- and first-excited states of selected p- and sd-shell nuclei, substantially advancing previous knowledge. Our results for ground states [2] are slightly larger compared with the somewhat...
The advanced emission Mössbauer spectrometer, eMiL (Emission Mössbauer from Ilmenau) was built for the emission Mössbauer (eMS) collaboration at ISOLDE/CERN. The set-up is based on the emission geometry and combines on-line and off-line isotope implantation used to measure hyperfine interactions in solids. Using radioactive Mössbauer probes that are ion-implanted to the sample by the GLM...
With the advent of nuclear structure studies using antiproton annihilations on the surface of unstable nuclei at the PUMA experiment [1], isobaric beam purity and vacuum requirements with < 1e-10 mbar motivate the installation of a new beamline at ISOLDE. A Multi-Reflection Time-of-Flight mass spectrometer (MR-ToF MS) is currently in commissioning at the MIRACLS experiment [2], promising up to...
We studied the transfer reactions with $^7$Be + $^{12}$C at 5 MeV/u. The measurements were carried out in the scattering chamber at HIE-ISOLDE using the pentagon detector array. Interestingly, for the $^7$Be nucleus having an $\alpha-$cluster structure and a low breakup threshold, transfer reactions are predominant than breakup$^1$.The transfer data leading to $^{16}$O* excited states are...
The Multi Ion Reflection Apparatus for Collinear Laser Spectroscopy (MIRACLS) is a new experiment in the ISOLDE facility at CERN which aims to conduct collinear laser spectroscopy (CLS) on exotic nuclei with low production yields by exploiting a 30-keV multi-reflection time-of-flight (MR-ToF) device [1]. Ions bunches prepared by MIRACLS’ Paul trap are sent into the MR-ToF instrument, where...
The β-decay of 8He and 9Li are observed as background in neutrino detectors where the detection mechanism is inverse β-decay by the reaction ν + p → e+ + n. Both nuclei have decay-branches that mimic this signal by emission of an electron and a neutron, which in addition to decay-decay branches of interest for pure nuclear physic motivates their study at the ISOLDE decay station, IDS.
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Measurements of the shape of the β energy spectrum are interesting to study, e.g., nuclear structure [1] and, when high precision is reached, allow to test for exotic scalar and/or tensor currents in the weak interaction [2].
However, the experimental precision reached is limited by the incomplete energy deposition caused by backscattering. In the WISArD set-up, this problem is alleviated...
The use of table-top high-precision measurements for studying physics beyond the standard model has become an alternative window to physical phenomena that are currently probed only by large-scale colliders like the LHC [1]. Among them, studies on diatomic molecules have become a promising quatum systems for diverse fields [2]. Even though most of these studies have been primarily with stable...
β detected NMR is a method to determine the magnetic moments of short-lived isotopes with a sensitivity inaccessible to conventional NMR. One of the isotopes scheduled to be investigated with β detected NMR at VITO is $^{11}\text{Be}$. It is of interest because it is a single neutron halo nucleus. Measuring the magnetic moment of $^{11}\text{Be}$ with greater accuracy will help to give insight...
Beta-detected nuclear magnetic resonance (β-NMR) is a sensitive technique, which has gained widespread recognition in the fields of nuclear physics [1] and materials science [2]. The recent utilization of ionic liquid targets has unlocked fresh opportunities for incorporating β-NMR spectroscopy into the domain of chemistry [3]. Precise determinations of the nuclear magnetic moments of β-NMR...
Naturally layered perovskites have been subject of great interest for novel technological applications, guiding, in particular, the extensive search for room-temperature (RT) magneto-electrics (ME). We aim to enhance the magneto and photo-induced effects in systems displaying Hybrid Improper Ferroelectricity (HIF) to achieve maximum energy conversion efficiencies in ME systems, thus exploring...
According to Benedek et. al [1], the CsNdNb$_{2}$O$_{7}$ system undergoes two phase transitions, one at 625 K and another at 800 K. Our objective is to investigate those three distinct phases: $P2_{1}am$ (# 26), $C2/m$ (# 12) and $P4/mmm$ (# 123) [1].
There is no existing literature discussing the magnetic state of CsNdNb$_{2}$O$_{7}$. Nevertheless, due to the presence of three unpaired...
Due to its low excitation energy around 8.3 eV, the unique $^{229}$Th isomer is, for now, the only candidate for developing a nuclear clock for, amongst others, fundamental physics studies~\cite{peik2015nuclear,thirolf2019improving}. In the past, measuring the isomer's radiative decay from a large-bandgap crystal with $^{229\text{m}}$Th embedded, has proven difficult: the commonly used...
On behalf of IS665 and IDS Collaboration.
Shape coexistence is a well-established phenomenon in which two or more different types of deformation coexist at low excitation energy within the same nucleus [1]. One of the most extensive manifestations of shape coexistence can be found in the neutron-deficient isotopes near the closed proton shell of lead (Z = 82). Exotic nuclei in this region...
The presence of both well-deformed prolate and oblate deformations are expected in the $A\approx70$ mass region because of the stabilisingly large single-particle energy gaps at $N=34$. Nonetheless, oblate deformations in this region has mostly been inferred from rotational bands ($^{68}$Se [1]) or model-dependent decay measurements ($^{72}$Kr [2]). Only recently, Coulomb-excitation...
In the A = 100 region, the dramatic shape change observed for Zr [1-3] and Sr [4-7] (Z = 40 and 38, respectively) is not present in Kr (Z = 36) isotopes [8-10]. The ${2}^{+}_{1}$ energies and the B(E2;${2}^{+}_{1}$ $\rightarrow$ ${0}^{+}_{1}$) values vary smoothly across the Kr isotopes. This is in contrast to the Sr and Zr isotopes which display a large jump at N = 60, indicating a...
β-NMR is a powerful method that exploits the asymmetry in the emission of β particles from spin-polarised, unstable nuclei. Combining a high degree of nuclear spin polarisation achieved through laser-induced optical pumping with an efficient detection yields a sensitivity up to ten orders of magnitude greater than conventional NMR. Its applications range from biochemistry to solid-state,...
Simple systems near the doubly-magic shell closures offer optimal scenarios for assessing the accuracy of shell-model predictions. While near the stability path, the predictions are consistent with experimental data; the nuclide properties change as we move away towards the neutron-rich nuclide. In this context, a comprehensive understanding of nuclear structure in the immediate vicinity of...
All-solid-state batteries (SSBs) present a potential route to address the poor range, slow charge, small temperature range of operation, and safety issues associated with traditional lithium-ion batteries.[1] However, one of the major limitations preventing SSBs to commercial market is the poor ionic conductivity of SSB materials, determined mostly by ion diffusion. Unlike other techniques to...
The future gamma-MRI imaging modality will allow the simultaneous exploitation the advantages of SPECT – sensitivity of gamma-ray detection, and MRI – spatial resolution and flexibility. The combination of these technique requires use gamma-emitting nuclei (like in SPECT) with highly polarized spins, leading to anisotropic emission of gamma-ray, and allowing spin manipulation with rf pulses...
The new research programme at VITO combines the strengths of β-decay spectroscopy and collinear laser spectroscopy. The design of an experimental station for studying the asymmetry of beta particle emission in coincidence with delayed radiation emitted from laser-polarised beams of neutron-rich nuclei involved technical solutions that balance the requirements of these two powerful techniques....
We present original high quality TDPAC data for Mn vanadates obtained during the last Cd run at ISOLDE together with possible interpretations and the discussion of related ambiguities.
The investigation of nuclei surrounding doubly-magic isotopes, such as $^{132}\mathrm{Sn}$, represents a fundamental approach for gaining deeper insights into the nuclear structure. However, the region of neutron-rich tin isotopes remains relatively unexplored, and experimental information is limited.
The only $\beta$-decay study of $^{124}\mathrm{In}$ to the excited states in...
Beta-decay spectroscopy is a powerful technique for studying the properties of exotic nuclei. Thanks to the high angular momentum selectivity of the process, beta decay offers unique access to states in daughter nuclei having configurations similar to the decaying precursors. However, the one major drawback of conventional beta-decay experiments is the limited ability to firmly assign spins...
Fine-structured designer materials for Radioisotope Production at CERN-ISOLDE
E. Reis1,2, V. Berlin2, S. Stegemann2, S. Bidhar3, D. C. Lupascu1, S. Rothe2
1Institute for Materials Science and Center for Nanointegration (CENIDE), University of Duisburg-Essen, Essen, Germany
2Center for European Nuclear Research, Geneva, Switzerland
3Fermilab National Accelerator Laboratory, Batavia,...
In a Forced-Electron Beam Induced Arc-Discharge Ion Source (FEBIAD) ion source [1], at ISOLDE called VADIS (VD), electrons are produced by resistively heating a cathode up to 2000 °C. Afterwards, they are accelerated towards an anode volume, by passing through a grid biased to an adjustable voltage. Atoms within the anode volume can then be ionized by electron impact or plasma ionization. In a...
Negative ion spectroscopy at CRIS-ISOLDE
Dag Hanstorp for the GANDALPH and CRIS collaboration
Negative ions are unique quantum systems to probe electron correlation effects: since the Coulomb potential of the nucleus is almost entirely screened, the binding of the additional electron is primarily due to many body interactions between electrons. Consequently, negative ions are sensitive...
The lanthanide elements, being located around the Z = 64 “sub-magic” proton subshell closure and all crossing the N = 82 neutron shell gap, offer a unique testing ground for nuclear theory. Benchmark cases range from strongly pronounced odd-even-staggering of charge radii vanishing in isomers (around Sm-141) [1], abrupt transitions from spherical to strongly deformed nuclei (for N < 75) [2],...
The design and simulation of an rf-atom/ion beam interaction region will be presented. The development of this region is needed to perform rf spectroscopy of short-lived radioactive atom or ion beams. In order to obtain the largest possible signal strength from rf spectroscopy, the field strength must be uniform across the atom/ion beam. In order to obtain this uniformity a vacuum spaced...
